Fuel injection nozzle for internal combustion engine and the like

ABSTRACT

A fuel injection nozzle of the type in which the needle valve and spring are eccentric and there is interposed between the needle valve and spring a low-mass hollow member having excellent bearing relation to the spring bore so as to prevent cocking and to enable the use of a spring of maximum diameter consistent with the diameter of the spring bore and the size of the needle valve.

United States Patent [191 Shipinski June 28, 1974 1 FUEL INJECTION NOZZLE FOR INTERNAL COMBUSTION ENGINE AND THE LIKE [75] Inventor: John Henry Shipinski, Cedar Falls,

Iowa

[73] Assignee: Deere & Company, Moline, Ill.

{22] Filed: Mar. 21, 1973 211 Appl. No.: 343,225

[52] US. Cl. 239/533 [51] Int. C1 B05b 1/30 [58] Field of Search 239/533 [56] References Cited UNITED STATES PATENTS 3,391,871 7/1968 Fleischer 239/533 3,499,607 3/1970 Thomson 239/533 3,695,235 10/1972 Anderson 239/533 X FOREIGN PATENTS OR APPLICATIONS 364,600 7/1930 Great Britain 239/533 1,117,256 2/1956 France 239/533 Primary EtaminerLl0yd L. King Assistant Eraminer-Andres Kashinkow ABSTRACT A fuel injection nozzle of the type in which the needle valve and spring are eccentric and there is interposed between the needle valve and spring a low-mass hollow member having excellent bearing relation to the spring bore so as to prevent cocking and to enable the use of a spring of maximum diameter consistent with the diameter of the spring bore and the size of the needle valve.

9 Claims, 3 Drawing Figures FUEL INJECTION NOZZLE FOR INTERNAL COMBUSTION ENGINE AND THE LIKE BACKGROUND OF THE INVENTION Fuel injection nozzles of the eccentric type referred to above are well known, as in the US. Pat. to Thomson No. 3,499,607 issued Mar. 10, 1970, the principal advantage of this type being that the overall diameter of the nozzle may be made quite small because the eccentricity of the needle valve and spring enables the use of a fuel passage alongside the spring bore. A disadvantage is that the spring does not act in perfect axial alignment with the needle valve and cocking of the parts may result. This cocking result may be avoided, according to the Thomson patent, by providing substantial guiding surfaces on the needle valve, best exemplified in that patent at column 4, lines 54-75. Nevertheless, it has been found that the Thomson design materially increases the mass and thus the inertia of the needle valve, and commercial variations have resorted to the use of a cup having an annular wall affording the requisite bearing surface but at the ex pense of seating the spring within the cup, from which it follows that a spring of smaller diameter must be used and therefore spring force is sacrificed.

Fuel injection nozzles are in a highly competitive field and any savings in cost, etc. are a plus, especially if the new design includes increases in value in areas of efficiency, manufacture, replacement, servicing, etc.

SUMMARY OF THE INVENTION According to the present invention, the above disadvantages are eliminated and many significant advantages are attained by a fuel injection nozzle of the eccentric type wherein there is interposed between the needle valve and spring a lightweight member that does not involve the reduction of spring diameter, nor does it entail increase in length, mass, etc., of the needle valve itself. Fundamentally, the member is hollow, light weight and has opposite ends abutting the spring and needle valve. No part of the spring-adjacent end of the member extends into the spring bore radially of the spring and thus the spring may be of a size that tolerably fits the bore; i.e., the spring may be of maximum diameter consistent with the spring bore diameter. Subsidiary features are thin-walled construction, bleed orifices, shouldered assembly, proportional design enabling selection of parts of optimum size, maximum efficiency, etc.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevation of one form of the preferred nozzle.

FIG. 2 is a longitudinal section of the same.

FIG. 3 is a fragmentary section of a modification.

DESCRIPTION OF THE PREFERRED EMBODIMENT The nozzle chosen for purposes of illustration comprises a nozzle body having an inner or injection end 12 and an outer or inlet end 14, the former having a needle valve bore 16 in which is disposed a needle valve 18 of conventional type in general. The bore '16 is coaxial with the overall structure of the body 10, and the nose end has outlets 20 that are opened and closed as the needle valve reciprocates in the bore 16. A

spring bore 22 is generally an extension or elongation of the needle valve bore but is eccentric thereto by a small amount, as explained in the Thomson patent, which enables the use of a fuel passage 24 alongside the spring bore and having an inlet end 26 (connected to the usual supply line, not shown) and leading to a chamber 28 by means of which the high-pressure fuel acts on th needle valve in a not unconventional man ner. All of this is well known, of course, and the present disclosure may be taken as typical of the fuel injection nozzle of the type characterized.

As the needle valve is intermittently displaced axially outwardly to inject fuel through the orifices or outlets 20 and into the typical combustion chamber, it must be rapidly returned to seated position by a spring, such as that shown at 30. As already elaborated, the spring bore 22 is eccentric to th needle valve, and it is likely that a cocking action will result. This is supposed to be solved in the Thomson patent by providing significant guiding surfaces between the needle valve and needle valve bore. But this results in increasing the size, weight and mass of the needle valve, even though it ent ables the use of a full-size spring in the spring hole.

The problem is that the spring cannot match the needle valve; i.e., the valve becomes so large that a suitable spring cannot be adapted to it without increasing the overall size of the nozzle body. To state the problem in a different way: with a fixed nozzle or needle valve size, the spring force must be such as to assure rapid closing of the valve so as to avoid the occurrence of fuel droplets and dribble at the end of injection, thus reducing the emission of soot, unburned hydrocarbons and carbon monoxide in the exhaust. Further, any increased length of the needle valve entails the possibility of bending it, and this would of course impair the efficient operation of the entire device. Increased length of the needle valve means of course increased mass and this leads to the requirement of a larger spring and this in turn requires enlargement of the entire body, which cannot be tolerated from the cost, etc., standpoints.

Now, according to the present invention, the above requirements are met in a simple and economical manner; namely, by use of a properly sized needle valve, a substantially large-diameter spring and retention of the overall size of the entire device within acceptable limits. This is largely achieved by the interposition of a member 32 between the outer end of the needle valve and the proximate end of the spring 30.

This member is cylindrical and hollow and includes a cup-shaped part made up of an annular wall 34 and a closed end 36 against which the spring 30 abuts. The other end of the cup is internally shouldered at 38 and tightly receives an externally shoulder circular end part 40. The cylindrical surface of the member is finely finished, as is the interior of the spring bore 22 so that the member is accurately guided in the bore as it moves axially back and forth in response to opening and closing of the needle valve. The axial length of the member, here preferably on the order of one-third to one-fifth that of the needle valve, is sufficient to preclude cocking or other misalignment of the member even though it is eccentric to the needle valve. Being hollow, the member has a small mass and thus low inertia. At the same time, its diameter, preferably on the order of four times that of the needle valve bore, is sufficiently large as to enable the use of a spring having a comparable diameter, all without using a spring of excessive length and without requiring any increase in the overall size of the entire device. Preferably, the length of the spring is on the order of twice the axial length of the member 34. The end 40 has a small bore 42 therethrough and a sim ilar bore 44 is provided in the end 36. Fuel leakage past the needle valve is accommodated by these bores in conjunction with a small hole 46 in the main body so that fluid buildup within the spring bore is avoided.

In the modified form shown in FIG. 3, a member 320, like the member 32 except for an axial extension 33 that fits within the spring 30, functions in the manner described above as respects the member 32. The provision of the extension 33 does not entail the reduction of spring diameter as would an inverted cup of the type previously referred to herein as a variation of the design of the Thomson patent.

I claim:

1. A fuel injection nozzle of the type in which the axially reciprocatable needle valve is acted on by a spring contained in a spring bore that is eccentric to the needle valve, characterized in that there is disposed in the spring bore an axially reciprocatable member between the spring and needle valve, said member being of hollow cylindrical form and of substantial axial length so as to provide a good bearing surface with the spring bore to prevent cocking of the member in the bore, the member having axially spaced apart opposite ends, one of which abuts the needle valve and the other of which is abutted by the spring, the member being of relatively light-weight construction so as to reduce weight and mass and the spring being of such diameter as to tolerably fit the bore whereby to increase its force on the member and through the member to the needle valve.

2. The invention defined in claim 1 in which the member end abutted by the spring is free from axial extensions into the spring bore radially outwardly of the spring diameter.

3. The invention defined in claim 1 in which the member is in the form of a cup having an annular wall fitting the spring bore and an integral end abutted by the spring and a closure end abutting the needle valve.

4. The invention defined in claim 3 in which the ends of the member have orifices therein.

-5. The invention defined in claim 1 in which the axial length of the member is on the order of one-third to one-fifth that of the needle valve.

6. The invention defined in claim 5 in which the spring is a coil spring having a normal length of approximately twice that of the member.

7. The invention defined in claim 1 in which the diameter of the member is approximately four times that of the needle valve at the injection end of said valve.

8. The invention defined in claim 1 in which the member has a relatively thin annular wall and relatively thin ends.

9. The invention defined in claim 2 in which the needle-valve proximate end of the cup-shaped member is internally shouldered and the closure is cooperatively externally shouldered to tit.

UNITED STATES PATENT OFFICE, CERTIFICATE OF CORRECTION Patent No. 3,820,723 Dated 28 June 197 Inventor(s) John Henry Shipinski It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

'Column I, Line 1 of Claim 9, change "2" to 3 Signed and sealed this 19th day of November 1974.

(SEAL) Attest:

MCCOY M. GIBSON JR. c. MARSHALL DANN' Attesting Officer Commissioner of Patents FORM Po-wso (10-69) USCOMMDC I v 4' ".5. GOVERNMENT PRINTING OFFICE l9! O3l6-3!|. 

1. A fuel injection nozzle of the type in which the axially reciprocatable needle valve is acted on by a spring contained in a spring bore that is eccentric to the needle valve, characterized in that there is disposed in the spring bore an axially reciprocatable member between the spring and needle valve, said member being of hollow cylindrical form and of substantial axial length so as to provide a good bearing surface with the spring bore to prevent cocking of the member in the bore, the member having axially spaced apart opposite ends, one of which abuts the needle valve and the other of which is abutted by the spring, the member being of relatively light-weight construction so as to reduce weight and mass and the spring being of such diameter as to tolerably fit the bore whereby to increase its force on the member and through the member to the needle valve.
 2. The invention defined in claim 1 in which the member end abutted by the spring is free from axial extensions into the spring bore radially outwardly of the spring diameter.
 3. The invention defined in claim 1 in which the member is in the form of a cup having an annular wall fitting the spring bore and an integral end abutted by the spring and a closure end abutting the needle valve.
 4. The invention defined in claim 3 in which the ends of the member have orifices therein.
 5. The invention defined in claim 1 in which the axial length of the member is on the order of one-third to one-fifth that of the needle valve.
 6. The invention defined in claim 5 in which the spring is a coil spring having a normal length of approximately twice that of the member.
 7. The invention defined in claim 1 in which the diameter of the member is approximately four times that of the needle valve at the injection end of said valve.
 8. The invention defined in claim 1 in which the member has a relatively thin annular wall and relatively thin ends.
 9. The invention defined in claim 2 in which the needle-valve proximate end of the cup-shaped member is internally shouldered and the closure is cooperatively externally shouldered to fit. 